The present invention relates to an apparatus for monitoring, preferably arrival monitoring, of the weft, e.g. the weft thread, in a loom of substantially the type in which the weft is driven through the shed with the aid of a jet, preferably a gas jet, e.g. an air jet, and which has a reed which is constructed from a number of lamellae disposed vertically with spacing, and which is pivotal between a first position and a second position and has a longitudinal channel for the weft.
Prior art arrival indicators suffer from an unreliable function which manifests itself primarily in many error signals and in many missed actual error trigger situations. These problems are accentuated particularly in air powered looms, so-called jet looms, which are extraordinarily quick and operate at high speeds such as 20 picks per second, in which event the arrival sensing must be executed during approximately 10-15 per cent of a complete machine cycle (5 per cent of the revolution). This naturally places extreme demands on the indicator itself and the associated electronics, in particular as regards sensitivity and speed. A major inconvenience in prior art arrival indicators is a very high degree of wear, which necessitates replacement of the indicator after short operational lives such as one month.